The adjective ravishing describes something or someone of exceptional beauty. If you say the dress your friend picked for the prom is ravishing, you mean it's beautiful and she looks beautiful in it.
The adjective ravishing comes from the verb ravish, which is from the Latin word rapere, meaning to seize. In English, the verb meant to plunder or to carry away, and later a sense arose that meant to carry away in pleasure, or to seduce. So a dress that is ravishing is seductive or sexy––or, as the word became more popular, simply beautiful, as in "ravishing scenery."